1. Field of the Invention
The present invention relates to optical switches which can control an operation of a circuit by detecting, as a switching signal, existence of a substance of various kinds such as pathogens, physiological substances, and toxic substances, and which can be applied to various safety apparatuses; and safety apparatuses using the optical switches.
2. Description of the Related Art
To date, many kinds of optical switching circuits have been proposed (see, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 2002-208720 and 2002-350748). However, they employ semiconductors, mirrors, or the like, and none is known that utilizes detecting the change of the wavelength of light. Furthermore, with regards to optical switches which use the wavelength change of light, ones that can control an operation of a circuit by detecting existence of various substances such as pathogens, physiological substances, and toxic substances as a switching signal and that can be applied to various safety apparatuses are yet to be provided.
On the other hand, in waste water treatment processes and the like, the safety of the waste water was achieved by detecting existence of toxic substances by, for example, inspecting the survival of fish such as carp that had been released in a lagoon where the waste water was kept before being released to a river, or by analyzing samples of the waste water at constant intervals. However, these processes had problems including that continuous processing is not possible, that they are complex, and that they do not provide sufficient safety. Although, some safety apparatuses which employ optical switches have been proposed (see, for example, JP-A Nos. 2001-63944 and 10-198426), these are not the ones which operate upon detecting a slight change of wavelength.
Objects and Advantages
An object of the present invention is to provide optical switches which can control an operation of a circuit by detecting, as a switching signal, existence of a substance of various kinds such as pathogens, physiological substances, and toxic substances, and which can be applied to various safety apparatuses.
Another object of the present invention is to provide safety apparatuses which are suitable for hospitals, laboratories, factories, plants, and the like, and which can avoid a hazard by activating a hazard evasive apparatus upon detecting, as a hazard signal, existence of a substance of various kinds such as pathogens, physiological substances, and toxic substances.